Are you ready for the ultimate field trip? We?ll start in our own cosmic neighborhood, the Milky Way, then zoom out to other galaxies of the universe. You?re about to discover that one size (or shape) fits all definitely doesn?t apply to these huge collections of stars, gas, and dust.

Frank Summers is an astronomer at the American Museum of Natural History. He knows all about galaxies and has answered a few questions submitted by kids like you. At each stop along the tour, click the audio file to hear his response.

You will need RealPlayer 7 to listen to the audio files. Clickherefor a free download.